Simplify the following expression: $q = \dfrac{7}{9n} + \dfrac{1}{6n}$
Answer: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $9n$ and $6n$ $\lcm(9n, 6n) = 18n$ $ q = \dfrac{2}{2} \cdot \dfrac{7}{9n} + \dfrac{3}{3} \cdot \dfrac{1}{6n} $ $q = \dfrac{14}{18n} + \dfrac{3}{18n}$ $q = \dfrac{14 +3}{18n}$ $q = \dfrac{17}{18n}$